The USSR is sort of Atlantis. It collapsed, but it gave birth to human travel in space and other useful gigs.
And it is often mentioned at HN, since most of the Russian engineers born in 1968-75 learned the math the beautiful Soviet way with Skanavi drillbook.
The USSR made some amazing contributions to technology, but it's a bit of an exaggeration to say that it "gave birth to human travel in space" which to me implies that it was a novel technology nobody else was working on and wouldn't have happened any time soon without them.
The first manned US flight was a month after the Soviet one, and the US had successfully returned monkeys from space before that, so arguably they were ahead technologically but less willing to use a human test subject.
It's more accurate to say that ICBM development in both the US and USSR had the unintended side-effect of giving birth to human space travel once the political benefits of using nuclear launch systems for human space travel were realized.
Well, USSR sort of had it right. This is why the US is still buying that rocket engines for new launches, designed more than 30 years ago in the "Atlantis".